1. Technical Field
The present invention relates to methods for manufacturing capacitors.
2. Related Art
In recent years, ferroelectric memories (FeRAMs) are expected as one of next generation type memories. Ferroelectric memories are characterized by nonvolatility, high-speed operation and low-power consumption.
In ferroelectric memory devices the crystal state of ferroelectric films composed of ferroelectric material defines one of the factors that determine the characteristics of the devices. A process for manufacturing ferroelectric memories includes the steps of forming interlayer dielectric films and protection films, and a large amount of hydrogen is usually generated in these steps. In this instance, because ferroelectric films are formed from oxide, the oxide is reduced by hydrogen generated during the manufacturing process, which undesirably affects the characteristics of the ferroelectric memories.
For this reason, in an ordinary ferroelectric memory having a capacitor, a ferroelectric film may be covered by a hydrogen barrier film such as an aluminum oxide film in order to prevent deterioration of the characteristics of the ferroelectric film, thereby securing the reduction-resistance of the capacitor, Japanese laid-open patent application JP-A-2003-243625 is an example of related art.